Fluid flow switch having cup-shaped actuator



March 8, 1966 B. H. CLASON FLUID FLOW SWITCH HAVING CUP-SHAPED ACTUATOR Filed Aug. 9, 1965 INVENTOR.

C I V? W 2115' ATTORNEY Bar?!) 1'). C/ason United States Patent 3,239,623 FLUID FLOW SWITCH HAVING CUP-SHAPED ACTUATOR Bertil H. Clason, Flint, lVIlCIL, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Aug. 9, 1963, Ser. No. 300,997 5 Claims. (Cl. 20ll81.9)

This invention relates to electrical switches and more particularly to an improved electrical switch which is responsive to flow of an electrically nonconductive fluid.

it is an object of the present invention to provide an electrical switch that will control an indicating circuit in response to afluid flow.

It is another object of the present invention to provide an electrical switch suitable for mounting in a passage carrying fluid, said switch being lubricated by the fluid.

It is a further object of the present invention to provide a means for triggering an impulse to an indicating circuit in response to a flow of fluid.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of the present invention is clearly shown.

In the drawing:

The single figure drawing is a sectional view of a switch made in accordance with this invention illustrating the switch mounted in typical application.

Referring now to the drawing, a terminal 10, made of any well-known conductive material, is mounted in one end of a switch body 12. The terminal is insulated from said switch body by means of an insulating sleeve 14 which is held in firm engagement with one end of the switch body by being pressed between a surface 16 of the switch body and a crimped over portion 18 of the switch body. A contact plate 20 is insulated in its mounted position by being wedged between the insulating sleeve 14 and an insulating washer 22. The insulating washer 22 is firmly held against the surface 16 of the switch body 12 by being pressed against the surface by the insulating sleeve 14 in its mounting. The terminal 10 has a contact 24 in conductive engagement with the contact plate 20, thus completing an electrical path between the terminal 10 and a surface 26 of the contact plate 20.

Disposed in the opposite wall of the switch body 12 is a slidable pin contact 28. A conductive disk 30 is attached to one end of the slidable pin contact 28 in any conventional manner which allows electrical current to pass therebetween. The slidable pin contact 28 has a portion 32 of slightly greater diameter than the main body of the pin which passes through an aperture 34 in the contact plate 20. An insulating ring 36, made of any well-known resilient material, firmly engages the portion 32 of the slidable pin contact 28 and holds it centered in the aperture 34. The insulating ring 36 is of a sufficient durometer rating to maintain the portion 32 of the slidable pin contact 28 centered in the aperture 34 Without allowing the portion 32 to contact the sides of the aperture 34. The slidable pin contact 28 has a retaining ring 38 with a contoured surface 40 disposed to hold an actuator cup 42 in firm engagement with a surface 44 of the switch body 12. A spring 46 is kept partially depressed between the portion 32 of the slidable pin contact 28 and an inclined surface 48 of the switch body 12. The slidable pin contact 28 is disposed for slidable movement in an aperture 50 through one wall of the switch body 12. The switch body 12 has a 3,239,623 Patented Mar. 8, 1966 threaded portion 52 to facilitate the mounting of the switch body 12 in a fluid carrying passage 53.

In operation, the fluid flow switching device is mounted by means of the cooperation of the threaded portion 52 with a threaded aperture in a wall of a fluid carrying passage and a conductive path is established between the terminal 10 and a tell-tale lamp 54 to an ignition switch 56 from a power source 58 having one side grounded. The switch body 12 is likewise grounded. Under a noflow condition in the fluid passage 53 with the ignition switch 56 in the ON position, there is no current flow. As fluid flows in the fluid passage 53, a pressure is exerted on the side of the actuator cup 42. This force causes a portion 60 of the actuator cup 42 to pivot on the surface 44 of the switch body 12. As the actuator cup 42 pivots on thesurface 44, the contoured portion 40 rides on a substantially flat surface 62 of the actuator cup 42. This pivoting action draws the slidable pin contact through the aperture 50 of the switch body 12 and eventually causes the conductive disk 30 to come into contact with the contact plate 20. This creates a path for current flow from the battery to ground through the fluid flow switching device. This current flow causes the tell-tale lamp 54 to light and, thus, alerts one monitoring the tell-tale lamp of the flow of fluid in the fluid passage 53.

The fluid flow switching device can be calibrated to various degrees of fluid flow by increasing or decreasing the amount of tension in the spring 46. An outstanding feature of this invention is the omnidirectional response to fluid flow as well as the constant lubrication afforded the slidable pin contact on the edges of the aperture 50.

The utility of this invention is immediately seen in an application where it is mounted in the oil system of an internal combustion engine. The constant flow of fluid in such an engine is imperative for satisfactory performance as well as long life. The oil pumps usually provided in such an installation are geared to the engine and constantly provide a fluid pressure during the operation of the engine. However, it is possible for such a geared oil pump to operate normally where or when a passage provided for the movement of the oil is, in fact, blocked. This situation is illustrated diagrammatically in the drawing where an engine 64 has a gear driven oil pump 66 drawing oil from a sump or crankcase 68 and pumping said oil through a line 70 to a full flow oil filter 72 and back to the sump. If the filter 72 is blocked or any point in the line 70 is blocked, the oil pump continues to pressurize the line but no oil flow occurs. During this time, lubrication to various operating parts of the engine is halted. One monitoring the operation of this engine would have no knowledge of the destructive wear caused by such a lack of lubrication without a device of the type hereinbefore described.

It should be noted that this device is operative only to monitor the flow of a fluid that is not electrically conductive.

While the embodiment of the present invention, as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. An electrical switch for fluid systems comprising fixed contact means; movable contact means; a body having a fluid passage wherein is contained said fixed contact means that is engageable by said movable contact means disposed therein to close an electrical indicating circuit, and flow responsive means carried by said movable contact means and positioned in a non-conductive fluid in a fluid system to sense a change in fluid flow of said fluid system, said fixed and movable contact means being operative while submerged in the non-conductive fluid.

2. An electrical switch for energizing a tell-tale lamp comprising a hollow body carrying a non-conductive fluid a fixed contact plate, an external terminal insulatedly mounted in one wall of said body and extending into said hollow body to establish a conductive relationshipv with said fixed contact plate therein, a pin-shaped contact means passing through and being biased away from another wall of said body, said pin contact means having a conductive disk on one end thereof disposed in opposition to said contact plate and having another end in loose fitting engagement with an actuator means, said actuator means being disposed in a passage carrying a non-conductive fluid and pivoting on said pin contact means during fluid flow to draw said pin contact and carried conductive disk into engagement with said fixed contact plate in response to fluid flow in the passage.

3. The combination of an electrical indicating system for fluid flow and an electrical switch comprising a body having a compartment therein and first and second ends, said compartment having a portion for retaining a resilient means, a fixed terminal insulatedly mounted in a first end of said body and having a conductive plate extending into said compartment, a pin contact means extending through a second wall of said body and having a portion carrying a conductive disk extending into said compartment, said conductive disk being positioned in opposition to and biased away from said conductive plate, said pin having a flange with a rounded portion carrying a substantially cup-shaped member, said cup-shaped member being positioned in a fluid passage and pivotably mounted on the rounded flange portion of said pin and movable in response to a fluid flow in said passage thereby levering said pin contact toward said second end of the body whereby the pin-carried conductive disk is brought into electrical contact with said conductive plate allowing electrical current to flow therethrough.

4. A fluid flow switch for use with a passage carrying a nonconductive fluid comprising, a body mounted in one wall of the fluid passage, said body having a compartment in which a switching action occurs, an insulatedly mounted terminal having a conductive plate being disposed in one end of said body and extending into said compartment, a pin having a conductive disk on one end thereof being in sliding engagement with another end of said body, said pin being biased towards and extending into said compartment, said pin-carried disk carried by said pin in opposed juxtaposition to said terminal-carried conductive plate, an actuator means carried by said pin and being retained in biased engagement with a wall of said body while being disposed in suspension in the fluid passage, and an insulating guide mounted on said pin to allow the insulated passage of said pin through said conductive plate, said actuator means having a sufficient exposed area to offer a resistance to a flow of fluid in the passage, said actuator means being carried by said pincarried conductive disk to bring said disk into conductive engagement with the terminal-carried contact plate on the stimulus of fluid flow in said passage.

5. A fluid flow switch mountable in a fluid passage carrying nonconductive fluids therein comprising, a conductive plate, a conductive disk held in opposed juxtaposition to said conductive plate within a compartment, pin means slidably mounted in the compartment, actuator means being mounted in loose engagement with said pin means, said pin means passing through said conductive plate in insulated relationship thereto and being engaged with said conductive disk whereby a flow of fluid in the passage will cause the actuator means to bring said conductive plate and conductive disk into engagement with one another thereby completing a path for electrical current flow therethrough.

References Cited by the Examiner UNITED STATES PATENTS 852,979 5/1907 Rice 200-81.9 1,856,584 5/1932 Parkhill 20081.9 2,773,251 12/1956 Snyder 200-81.9 2,879,892 4/1959 Frakes 2O081.9 X

BERNARD A. GILHEANY, Primary Examiner. 

1. AN ELECTRICAL SWITCH FOR FLUID SYSTEMS COMPRISING FIXED CONTACT MEANS; MOVABLE CONTACT MEANS; A BODY HAVING A FLUID PASSAGE WHEREIN IS CONTAINED SAID FIXED CONTACT MEANS THAT IS ENGAGEABLE BY SAID MOVABLE CONTACT MEANS DISPOSED THEREIN TO CLOSE AN ELECTRICAL INDICATING CIRCUIT, AND FLOW RESPONSIVE MEANS CARRIED BY SAID MOVABLE CONTACT MEANS AND POSITIONED IN A NON-CONDUCTIVE FLUID IN A FLUID SYSTEM TO SENSE A CHANGE IN FLUID FLOW OF SAID FLUID SYSTEM, SAID FIXED AND MOVABLE CONTACT MEANS BEING OPERATIVE WHILE SUBMERGED IN THE NON-CONDUCTIVE FLUID. 